From ac7ed464b5f85b1aff8224f061baa9b954abff7f Mon Sep 17 00:00:00 2001
From: Andi Gutmans <andi@php.net>
Date: Sun, 16 Dec 2001 19:45:49 +0000
Subject: [PATCH] - Start adding parsed variable checks.

---
 Zend/zend_compile.c         | 22 ++++++++++++++++++++++
 Zend/zend_compile.h         |  2 ++
 Zend/zend_language_parser.y |  7 ++++---
 3 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/Zend/zend_compile.c b/Zend/zend_compile.c
index 0b753f23d6..b74946b96f 100644
--- a/Zend/zend_compile.c
+++ b/Zend/zend_compile.c
@@ -528,6 +528,28 @@ void zend_do_if_end(TSRMLS_D)
 	DEC_BPC(CG(active_op_array));
 }
 
+#if 0
+/* variable parsing type (compile-time) */
+#define ZEND_PARSED_MEMBER			(1<<0)
+#define ZEND_PARSED_METHOD_CALL		(1<<1)
+#define ZEND_PARSED_STATIC_MEMBER	(1<<2)
+#define ZEND_PARSED_FUNCTION_CALL	(1<<3)
+#define ZEND_PARSED_VARIABLE		(1<<4)
+
+#endif
+
+void zend_check_writable_variable(znode *variable)
+{
+	zend_uint type = variable->u.EA.type;
+	
+	if (type & ZEND_PARSED_METHOD_CALL) {
+		zend_error(E_ERROR, "Can't use method return value in write context");
+	}
+	if ((type & ZEND_PARSED_FUNCTION_CALL) &&
+		!(type & (ZEND_PARSED_METHOD_CALL|ZEND_PARSED_MEMBER))) {
+		zend_error(E_ERROR, "Can't use function return value in write context");
+	}
+}
 
 zend_bool zend_variable_buffer_empty(TSRMLS_D)
 {
diff --git a/Zend/zend_compile.h b/Zend/zend_compile.h
index 76dd43e7a2..a7c8b9159a 100644
--- a/Zend/zend_compile.h
+++ b/Zend/zend_compile.h
@@ -259,6 +259,8 @@ void zend_do_post_incdec(znode *result, znode *op1, int op TSRMLS_DC);
 void zend_do_begin_variable_parse(TSRMLS_D);
 void zend_do_end_variable_parse(int type, int arg_offset TSRMLS_DC);
 
+void zend_check_writable_variable(znode *variable);
+
 void zend_do_free(znode *op1 TSRMLS_DC);
 
 void zend_do_init_string(znode *result TSRMLS_DC);
diff --git a/Zend/zend_language_parser.y b/Zend/zend_language_parser.y
index 09764324e1..01057699cb 100644
--- a/Zend/zend_language_parser.y
+++ b/Zend/zend_language_parser.y
@@ -613,12 +613,13 @@ r_cvar:
 
 
 w_cvar:
-	cvar { zend_do_end_variable_parse(BP_VAR_W, 0 TSRMLS_CC); $$ = $1; }
+	cvar	{ zend_do_end_variable_parse(BP_VAR_W, 0 TSRMLS_CC); $$ = $1; }
+			{ zend_check_writable_variable(&$$); }
 ;
 
-
 rw_cvar:
-	cvar { zend_do_end_variable_parse(BP_VAR_RW, 0 TSRMLS_CC); $$ = $1; }
+	cvar	{ zend_do_end_variable_parse(BP_VAR_RW, 0 TSRMLS_CC); $$ = $1; }
+			{ zend_check_writable_variable(&$$); }
 ;
 
 r_cvar_without_static_member:
-- 
2.50.1